Shortly after 11 p.m. on 10/11/2012, an explosion tore through the Richmond Hill residential area in southern Indianapolis.

The blast leveled one house and severely damaged dozens of others, scattering insulation, wood, and household items throughout the neighborhood. Surviving residents emerged to find many homes engulfed in flames, while others were reduced to rubble.

Hundreds of Indianapolis police cars, fire trucks, and rescue workers converged on the neighborhood on the night of the 10/11/2012 explosion. Fires burned for hours after the initial blast. Photo: The Star

The home of Monserrate Shirley was at the epicenter of the destruction, but the two fatalities were her next-door neighbors: Jennifer Longworth, 36 years old, and her husband John "Dion" Longworth, 34 years old.

Jennifer died instantly in the initial explosion. Dion survived the blast but was trapped in the basement of his burning home, succumbing to smoke and heat inhalation, along with severe burns.

7 others sustained injuries, and approximately 80 homes were affected, with total damages estimated to exceed USD 3 million.

"At first, we thought it was a bomb. Our entire house felt like it was lifted off its foundation," a neighbor of Shirley's recounted.

Shirley owned the house where the explosion originated. She lived there with her boyfriend, Mark Leonard. The couple claimed the explosion was a tragic accident and denied any involvement, a narrative initially accepted by neighbors and police. However, the situation changed within a few days as the investigation progressed.

**Following the trail**

Initially, authorities investigated the possibility that the explosion was caused by a malfunctioning appliance or a gas supply system failure. However, by 19/11/2012, they officially shifted their focus, classifying it as a criminal case.

An aerial view shows two homes leveled and many neighboring houses damaged by the explosion. Photo: WTHR Chopper13

Investigators discovered a television remote control in the house, but no television, and very few clothes or belongings. They also noted that at least two gas pressure regulator valves, which control the flow of gas into a home, were missing.

Detectives also found that the microwave oven was significantly more damaged than other electrical appliances in the house, leading them to suspect it was used to trigger the explosion. They seized a metal container that potentially held "liquid explosives or some chemical." Prosecutors alleged the suspects placed the container in the microwave and used its timer function to generate a spark, causing the explosion after they had left the scene.

At the time of the explosion, Shirley and Mark were confirmed to be at a casino, though they had no intention of staying overnight. Shirley's daughter and the family cat had also been sent elsewhere for care.

Further investigation revealed that prior to the explosion, Mark and his brother Bob had met with a former gas company employee to learn "basic information about how to cause an explosion."

Bob's DNA was found on Shirley's front door after the explosion, leading investigators to believe he set the microwave timer to trigger the blast.

Investigators also tracked a white truck seen at Shirley's home that day, identifying it as belonging to Bob.

On 21/12/2012, Shirley and the Leonard brothers were arrested on charges of murder and conspiracy to commit arson.

**The plot behind the blast**

Shirley agreed to cooperate with prosecutors. In 2015, she pleaded guilty to two counts of conspiracy to commit arson and testified against the Leonard brothers.

According to Shirley's court testimony, in 2/2012, Mark proposed burning down the house to collect USD 300,000 in insurance money. Shirley recalled Mark telling her he "would show her how to make money." She claimed the initial plan was to increase the home's insurance coverage, then set fire to the garage.

"I thought it was crazy, but I followed him," Shirley testified.

Investigators discovered Shirley and Mark carried approximately USD 63,000 in credit card debt, were undergoing bankruptcy proceedings, and had taken out a second mortgage on the house. Mark also reportedly lost about USD 10,000 at a casino just weeks before the explosion.

Mark was accused of orchestrating the plan to destroy the house and recruiting his brother Bob, promising him USD 10,000.

**Two failed attempts**

The explosion on 10/11/2012 was not the first time the group tried to burn down the house.

Investigators determined the group had attempted to destroy the house on the two preceding weekends. Each time, Shirley and Mark left town for a casino, sent their daughter and cat elsewhere, and removed valuables from the house. These precautions were also taken before the final, successful attempt.

Another individual involved, Gary Thompson, assisted in the preparations for the prior failed attempts but later withdrew from the plan.

In 2015, Gary and a fifth suspect, Glenn Hults, were arrested.

Monserrate Shirley is escorted from court after her plea agreement hearing on 20/1/2015. Photo: Indy Star

In 7/2015, a jury convicted Mark of all 53 counts, including two counts of murder and multiple counts of arson and conspiracy to commit insurance fraud. He received two consecutive life sentences without parole, plus 75 years in prison.

Bob was convicted of all 51 charges, including felony murder, in 2/2016. He received two consecutive life sentences without parole, plus 70 years in prison.

Shirley received the maximum sentence allowed under her plea agreement: 50 years in prison. At her sentencing, the judge noted that Shirley protected her daughter, cat, and belongings by removing them from the house, but did nothing to protect her neighbors.

Gary pleaded guilty to one count of conspiracy to commit arson and received a 30-year prison sentence, with 10 years suspended. Glenn received a 3-year prison sentence for assisting a criminal, having known about the plan and cared for Shirley's daughter.

Mark died at 48 years old from illness while serving his sentence on 30/1/2018, less than three years after being convicted of orchestrating the insurance fraud that killed two people and turned a residential area into the scene of one of the city's most destructive crimes.

Tue Anh (according to AETV, People)